Poverty can be defined as poor purchasing power

The report found that the official poverty rate and the Census Bureau’s new Supplemental Poverty Measure—both of which are income-based—do not gauge the extent of poverty as well as a method based on real purchasing ability.

Meyer and Sullivan find their consumption-based measure better captures more of the most disadvantaged than those based on income, because it accounts for savings usage, ownership of durable goods, access to credit and the use of anti-poverty programs. The most disadvantaged families also appear to report their consumption more accurately than income.

Read more at: http://phys.org/news/2012-08-consumption-poverty-income.html#jCp